Field Of The Invention
The invention relates to a chain conveyor for transporting sheets in a printing press, having two conveyor chains disposed opposite one another and revolving together during operation, and at least one gripper bar extending in the longitudinal direction thereof between the two conveyor chains and being connected at a respective end thereof to one of the conveyor chains, and also relates to a sheet-processing printing press equipped with the chain conveyor.
A chain conveyor of the aforementioned type has been disclosed heretofore, for example, in the published European Patent Document EP 0 669 210 A1. In this regard, a connection between a conveyor chain and the gripper bar is produced by a carrier which is divided into two parts of which a first part is connected to the gripper bar and a second part to the conveyor chain, the two parts being received telescopically in one another in a direction parallel to the travel path of the conveyor chain and being threadedly secured or screwed to one another in the direction in which they are joined.
Therewith, and indeed in the unscrewed condition thereof, i.e., in the condition thereof that is not suitable for the intended operation of the chain conveyor, the gripper bar can easily be disassembled by displacing it parallel to the travel path of the conveyor chain, if it should have become damaged due to a process failure and requires replacement or repair.
The gripper bars of the foregoing chain conveyors carry grippers which close under spring force and which, when in operation, are opened periodically, so that periodic gripper opening forces act upon the conveyor chains. With regard to the heretofore known chain conveyors of the type mentioned in the introduction hereto, these gripper opening forces are absorbed by chain guide tracks, as are centrifugal forces occurring in the returning or reversing regions of the conveyor chains. In order to avoid over-dimensioning of the width of the chain guide track and the length of the chain rollers of the roller chains which are employed as conveyor chains in the case of the foregoing chain conveyors so as to attain an acceptable pressure between the chain guide track and the chain rollers, it is therefore desirable to support the chain rollers on the chain guide tracks as much as possible over the entire extent thereof between the inner fitting plates of the roller chains. This is countered, however, by the fact that, in this case, particularly at the side surfaces of the chain guide tracks which face the gripper bar, considerable wear occurs if, as a result of production and installation tolerances, stresses occur between the chain guide tracks and the conveyor chains.